Medical Dictionary

malignant

adj ma·lig·nant \mə-ˈlig-nənt\

Medical Definition of MALIGNANT

1
:  tending to produce death or deterioration <malignant malaria>; especially :  tending to infiltrate, metastasize, and terminate fatally <malignant tumors>—compare benign 1
2
:  of unfavorable prognosis :  not responding favorably to treatment <psychotic reactions with a malignant trend>
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